# Correction to: Retrieval

Correction

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Part of the Health Informatics book series (HI)

## Correction to: Chapter 5 in: W. Hersh, Information Retrieval: A Biomedical and Health Perspective, Health Informatics, https://doi.org/10.1007/978-3-030-47686-1_5

The original version of the book was inadvertently published with wrong Equations 5.2, 5.3 and 5.4, and the revised equations were updated in the chapter as follows,

$$\mathrm{Document}\ \mathrm{weight}=\frac{\sum \limits_{\mathrm{all}\ \mathrm{query}\ \mathrm{term}\mathrm{s}}\left(\mathrm{Weight}\ \mathrm{of}\ \mathrm{term}\ \mathrm{in}\ \mathrm{query}\ast \mathrm{Weight}\ \mathrm{of}\ \mathrm{term}\ \mathrm{in}\ \mathrm{document}\right)}{\sqrt{\left(\sum \limits_{\mathrm{all}\ \mathrm{query}\ \mathrm{term}\mathrm{s}}\mathrm{Weight}\ \mathrm{of}\ \mathrm{term}\ {\mathrm{in}\ \mathrm{query}}^2\right)\ast \left(\sum \limits_{\mathrm{all}\ \mathrm{document}\ \mathrm{term}\mathrm{s}}\mathrm{Weight}\ \mathrm{of}\ \mathrm{term}\ {\mathrm{in}\ \mathrm{document}}^2\right)}}$$
(5.2)
$${\displaystyle \begin{array}{l}\mathrm{New}\ \mathrm{query}\ \mathrm{weight}=\\ {}\alpha \ast \mathrm{Original}\ \mathrm{query}\ \mathrm{weight}\\ {}+\beta \ast \frac{1}{\mathrm{number}\ \mathrm{of}\ \mathrm{relevant}\ \mathrm{document}\mathrm{s}}\ast \sum \limits_{\mathrm{all}\ \mathrm{relevant}\ \mathrm{document}\mathrm{s}}\mathrm{weight}\ \mathrm{in}\ \mathrm{document}\\ {}-\gamma \ast \frac{1}{\mathrm{number}\ \mathrm{of}\ \mathrm{nonrelevant}\ \mathrm{document}\mathrm{s}}\ast \sum \limits_{\mathrm{all}\ \mathrm{nonrelevant}\ \mathrm{document}\mathrm{s}}\mathrm{weight}\ \mathrm{in}\ \mathrm{document}\end{array}}$$
(5.3)
$${\displaystyle \begin{array}{l}\mathrm{New}\ \mathrm{query}\ \mathrm{weight}=\\ {}\mathrm{Original}\ \mathrm{query}\ \mathrm{weight}\\ {}+\mathrm{Average}\ \mathrm{term}\ \mathrm{weight}\ \mathrm{in}\ \mathrm{relevant}\ \mathrm{documents}\\ {}-\mathrm{Average}\ \mathrm{term}\ \mathrm{weight}\ \mathrm{in}\ \mathrm{nonrelevant}\ \mathrm{documents}\end{array}}$$
(5.4)

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### Cite this chapter

Hersh, W. (2020). Correction to: Retrieval. In: Information Retrieval: A Biomedical and Health Perspective. Health Informatics. Springer, Cham. https://doi.org/10.1007/978-3-030-47686-1_9

• DOI: https://doi.org/10.1007/978-3-030-47686-1_9

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• Publisher Name: Springer, Cham

• Print ISBN: 978-3-030-47685-4

• Online ISBN: 978-3-030-47686-1

• eBook Packages: MedicineMedicine (R0)